EP2519804B1 - Measuring system comprising a vibration-type transducer - Google Patents

Description

The invention relates to a, especially as a compact meter and / or a Coriolis Massedurchfluß measuring instrument trained, measuring system for flowable, esp. Fluid, media, which at least temporarily flowed through during operation of medium, characterized by at least one of the flowing medium Measured variable, in particular a mass flow, a density, a viscosity, etc., influenced vibration-type primary signals generating primary signals as well as a converter electronics electrically coupled to the transducer and supplied by the transducer primary signals to measured values.

In industrial measuring technology, especially in connection with the regulation and monitoring of automated process engineering processes, such measuring systems are often used to determine characteristic measured variables of media flowing in a process line, for example a pipeline, for example liquids and / or gases which induce reaction forces, for example Coriolis forces, in the flowing medium by means of a transducer of the vibration type and a converter electronics connected thereto, usually accommodated in a separate electronics housing, and return the at least one measured variable, for example a mass flow rate, of a density , a viscosity or another process parameter, correspondingly generate measured values. Such measuring systems, often formed by means of an in-line meter in compact design with integrated transducer, such as a Coriolis mass flow meter, have long been known and have proven themselves in industrial use. Examples of such measuring systems with a transducer of the vibration type or individual components thereof are, for example in the EP-A 317 340 , the JP-A 8-136311 , the JP-A 9-015015 , the US-A 2007/0119264 , the US-A 2007/0119265 , the US-A 2007/0151370 , the US-A 2007/0151371 , the US-A 2007/0186685 , the US-A 2008/0034893 , the US-A 2008/0141789 . US-A 46 80 974 , the US-A 47 38 144 , the US-A 47 77 833 , the US-A 48 01 897 , the US-A 48 23 614 , the US-A 48 79 911 , the US-A 50 09 109 , the US-A 50 24 104 , the US-A 50 50 439 , the US-A 52 91 792 , the US-A 53 59 881 , the US-A 53 98 554 , the US-A 54 76 013 , the US-A 55 31 126 , the US-A 56 02 345 , the US-A 56 91 485 , the US-A 57 34 112 , the US Pat. No. 5,796,010 , the US Pat. No. 5,796,011 , the US Pat. No. 5,796,012 , the US-A 58 04 741 , the US-A 58 61 561 , the US-A 58 69 770 , the US-A 59 45 609 , the US-A 59 79 246 , the US-A 60 47 457 , the US-A 60 92 429 , the US-A 6073495 , the US-A 63 111 36 , the US-B 62 23 605 , the US-B 63 30 832 , the US-B 63 97 685 , the US-B 65 13 393 , the US-B 65 57 422 , the US-B 66 51 513 , the US-B 66 66 098 , the US-B 66 91 583 , the US-B 68 40 109 , the US-B 68 68 740 , the US-B 68 83 387 , the US-B 70 17 424 , the US-B 70 40 179 , the US-B 70 73 396 , the US-B 70 77 014 , the US-B 70 80 564 , the US-B 71 34 348 , the US-B 72 16 550 , the US-B 72 99 699 , the US-B 73 05 892 , the US-B 73 60 451 , the US-B 73 92 709 , the US-B 74 06 878 , the WO-A 00/14485 , the WO-A 01/02 816 , the WO-A 2004/072588 , the WO-A 2008/013545 , the WO-A 2008/077574 , the WO-A 95/29386 , the WO-A 95/16897 or the WO-A 99 40 394 described. Each of the transducers shown therein comprises at least one, in a transducer housing housed, substantially straight or curved measuring tube for guiding the, possibly also extremely fast or extremely slowly flowing medium. During operation of the measuring system, the at least one measuring tube is vibrated for the purpose of generating vibrations through the medium flowing through it.

For transducers with two measuring tubes, these are mostly integrated via an inlet flow divider extending between the measuring tubes and an inlet-side connecting flange and via an outlet-side flow divider extending between the measuring tubes and an outlet-side connecting flange into the process line. In transducers with a single measuring tube, the latter usually communicates via an inlet side opening substantially straight connecting pipe piece and an outlet side opening substantially straight connecting pipe piece with the process line. Furthermore, each of the transducers shown with a single measuring tube each comprising at least one integral or multi-part running, for example, tubular, box or plate-shaped counteroscillator, which is coupled to form a first coupling zone inlet side to the measuring tube and the outlet side to form a second coupling zone the measuring tube is coupled, and which rests in operation substantially or the measuring tube gegengleich, ie the same frequency and out of phase, oscillates. The inner part of the transducer formed by means of measuring tube and counteroscillator is mostly alone by means of two connecting pipe pieces, which communicates the measuring tube in operation with the process line, held in a protective transducer housing, esp. In a vibration of the inner part relative to the transducer housing enabling manner , For example, in the US-A 52 91 792 , the US Pat. No. 5,796,010 , the US-A 59 45 609 , the US-B 70 77 014 , the US-A 2007/0119264 , the WO-A 01 02 816 or even the WO-A 99 40 394 shown transducers with a single, substantially straight measuring tube are the latter and the counteroscillator, as quite common in conventional transducers, aligned with each other substantially coaxially. In marketable transducers of the aforementioned type is usually also the counteroscillator substantially tubular and formed as a substantially straight hollow cylinder, which is arranged in the transducer so that the measuring tube is at least partially encased by the counteroscillator. As materials for such counteroscillators, esp. When using titanium, tantalum or zirconium for the measuring tube, usually relatively inexpensive steel grades, such as mild steel or free-cutting steel used.

As an excited waveform - the so-called Nutzmode - is usually in transducers with curved, for example U-, V- or Ω-like shaped, measuring tube that Selected natural vibration mode in which the measuring tube oscillates at least proportionally at a lowest natural resonant frequency about an imaginary longitudinal axis of the transducer in the manner of a cantilevered at one end cantilever, whereby in the medium flowing through mass-dependent Coriolis forces are induced. These in turn cause the excited oscillations of the Nutzmodes, in the case of curved measuring tubes so pendulum-like boom oscillations, to the same frequency bending vibrations according to at least one also natural second waveform, the so-called Coriolis mode superimposed. In transducers with a curved measuring tube, these Coriolis force-forced cantilever oscillations in Coriolis mode usually correspond to those natural vibration modes in which the measuring tube also executes torsional vibrations about an imaginary vertical axis oriented perpendicular to the longitudinal axis. In the case of transducers with a straight measuring tube, on the other hand, such a useful mode is often selected for generating mass flow-dependent Coriolis forces, in which the measuring tube carries out bending oscillations substantially in a single imaginary plane of vibration, so that the oscillations in the Coriolis mode are correspondingly designed as bending vibrations of the same oscillation frequency that are coplanar with the useful mode oscillations are. Due to the superimposition of useful and Coriolis mode, the means of the sensor arrangement on the inlet side and outlet side detected vibrations of the vibrating measuring tube on a dependent on the mass flow, measurable phase difference. Usually, the measuring tubes of such, for example, used in Coriolis mass flow meters, transducers during operation at a momentary natural resonant frequency of the selected mode for the mode of vibration, esp. At constant-controlled oscillation amplitude, excited. Since this resonant frequency is particularly dependent on the instantaneous density of the medium, in addition to the mass flow rate, the density of flowing media can also be measured by means of commercially available Coriolis mass flow meters. Furthermore, it is also possible, such as in the US-B 66 51 513 or the US-B 70 80 564 shown to measure directly by means of transducers of the vibration type, viscosity of the medium flowing through, for example, based on a required for the maintenance of the vibrations excitation power or excitation power and / or based on a resulting from a dissipation of vibration energy damping vibrations of at least one measuring tube, esp those in the aforementioned Nutzmode. In addition, other, derived from the aforementioned primary measurements mass flow rate, density and viscosity measured variables, such as according to the US-B 65 13 393 the Reynolds number to be determined.

To excite vibrations of the at least one measuring tube, vibration-type transducers further comprise an electrical drive signal, eg a regulated current, driven exciter arrangement generated during operation of one of the mentioned driver electronics, which activates the measuring tube by means of at least one current during operation flowed through, on the measuring tube practically directly acting electro-mechanical, esp. Electro-dynamic, vibrator excites to bending vibrations in Nutzmode. Furthermore, such transducers comprise a sensor arrangement with, in particular electro-dynamic, vibration sensors for at least selective detection of inlet-side and Auslaßseitiger oscillations of the at least one measuring tube, esp. Those in Coriolis mode, and for generating the process parameters to be detected, such as the mass flow or the density , influenced, as primary signals of the transducer serving electrical sensor signals. Such as in the US-B 72 16 550 may also be used at least temporarily as a vibration sensor and / or a vibration sensor at least temporarily as vibration exciter at transducers of the type in question, the vibration exciter. The exciter arrangement of transducers of the type in question usually has at least one electrodynamic and / or differentially acting on the at least one measuring tube and the possibly existing counteroscillator or possibly existing other measuring tube vibration exciter, while the sensor arrangement an inlet side, usually also electrodynamic, Vibration sensor and at least one substantially identical outlet-side vibration sensor comprises. Such electrodynamic and / or differential vibration exciter commercially available transducers of the vibration type are at least temporarily by a current - in transducers with a measuring tube and a counteroscillator coupled thereto mostly fixed to the latter - magnetic coil and interacting with the at least one magnetic coil, esp. In this immersed, serving as an anchor rather elongated, esp. Rod-shaped, permanent magnet formed, which is fixed according to the measuring tube to be moved. The permanent magnet and serving as excitation coil magnetic coil are usually aligned so that they are substantially coaxial with each other. In addition, in conventional transducers, the exciter assembly is usually designed and placed in the transducer that it acts substantially centrally on the at least one measuring tube. In this case, the vibration exciter and insofar the exciter arrangement, as for example in the in the US Pat. No. 5,796,010 , the US-B 68 40 109 , the US-B 70 77 014 or the US-B 70 17 424 shown proposed transducers, usually fixed at least at certain points along an imaginary central circumferential line of the measuring tube outside of this. As an alternative to an exciter arrangement formed by means of vibration exciters acting more centrally and directly on the measuring tube, such as in the US-B 65 57 422 , the US-A 60 92 429 or the US-A 48 23 614 proposed, for example, by means of two not in the center of the measuring tube, but rather on the inlet or outlet side formed on this fixed vibrator exciter arrangements are used or, as in the US-B 62 23 605 or the US-A 55 31 126 proposed, for example, by means of a formed between the possibly existing counteroscillator and the transducer housing vibration exciter arrangements are used. For most commercially available transducers of the vibration type, the vibration sensors of the sensor arrangement, as already indicated, at least to the extent substantially identical in construction as the at least one Vibration generator, as they work on the same principle of action. Accordingly, the vibration sensors of such a sensor arrangement are usually each by means of at least one - usually at the existing counter-oscillator - at least temporarily interspersed by a variable magnetic field and thus at least temporarily acted upon by an induced measuring voltage and fixed to the measuring tube, with the at least one Coil is made up of co-acting permanent magnetic armature that provides the magnetic field. Each of the aforementioned coils is also connected by means of at least one pair of electrical leads with the mentioned converter electronics of the in-line measuring device, which are usually performed on the shortest path from the coils on the counteroscillator towards the transducer housing.

As, inter alia, in the above-mentioned US-B 74 06 878 . US-B 73 05 892 . US-B 71 34 348 . US-B 65 13 393 . US-A 58 61 561 . US-A 53 59 881 or. WO-A 2004/072588 discussed, another, relevant for the operation of the measuring system as such and / or for the operation of the system in which the measuring system is installed, relevant parameters - for example, by the transducer and insofar as the measuring system itself provoked - pressure drop in the flow or be a resulting reduced pressure outlet side of the transducer, this not least also in the event that the medium is formed two- or multi-phase, such as a liquid-gas mixture, and / or that in operation with undesirable, not least the structural integrity of the Measuring converter hazardous cavitation due to falling below a minimum static pressure in the flowing medium to count or this is absolutely to be avoided. In the in the US-A 53 59 881 or the US-B 74 06 878 a measuring pressure drop across the transducer during operation is determined, for example, that at a first pressure measuring in the inlet region of the transducer or immediately upstream thereof by means of a first pressure sensor, a first static pressure in the flowing medium and at a second pressure measuring in the outlet of the transducer or immediately downstream thereof by means of an additional second pressure sensor detects a second static pressure in the flowing medium and, by means of a hydraulic pressure measuring device and / or by means of the respective converter electronics, is converted into a corresponding pressure difference measured value. In the US-B 73 05 892 or the US-B 71 34 348 Furthermore, a described by a transducer of the vibration type method for measuring a pressure difference is described in which based on a vibration response of the at least one measuring tube on a multimode vibration excitation and in the converter electronics deposited physical-mathematical models for dynamics of - here as Coriolis mass flow -Messgerät trained - measuring system, a pressure or a pressure drop in the medium flowing through the transducer is determined.

An object of the invention is therefore to improve by means of transducers of the vibration type measuring systems to the effect that for the purpose of detection or alarm undesirable high pressure drops in the flowing medium, esp. For the purpose of detecting too low a pressure within the medium flowing in the transducer or for the purpose of alarming imminent cavitation in the flowing medium, with the least possible effort sufficiently accurate, possibly also in the sense of generating validated measured values highly precise, measurement of a pressure downstream of the inlet end of the transducer in the medium flowing therethrough is possible; this in particular also under extensive use of the proven in such measuring systems measurement technique, such as established vibration sensors and / or aktorik, or even proven technologies and architectures of established converter electronics.

To solve the problem, the invention consists in a measuring system according to independent claim 1.

A basic idea of the invention is, in particular, also using a few measured values established for the measurement of the medium, such as density, viscosity, mass flow rate and / or Reynolds number, which are typically present anyway in measuring systems of the type in question be determined internally, and / or on the basis of a few, by means of the transducer electronics such Meßsysteme typically internally generated operating parameters, such as a phase difference between the inlet and outlet oscillations of the at least one measuring tube representing primary signals, their signal frequency and / or amplitude and Including a measured upstream of the transducer or downstream of the transducer or in the pipeline - for example by means of appropriately controlled pumps or valves - set the pressure in the internally running the converter electronics calculations as a further interesting measure a To determine pressure downstream of the inlet end of the transducer. The invention is also based on the surprising finding that even alone on the basis of the aforementioned operating parameters or derived therefrom, in measurement systems of the type in question typically measured values anyway and a few previously specifically - such as in the course of an already be performed wet calibration - too determining measuring system-specific fixed values, pressure drops in the medium flowing through the measuring transducer can be determined with a measurement accuracy which is also sufficient for alarming critical operating conditions, such as cavitation in the flowing medium; This also applies over a very wide Reynolds number range, ie for both laminar and turbulent flow. An advantage of the invention consists in particular in that for the realization of the pressure measurement according to the invention both on proven conventional transducers as well as on proven conventional - with regard to the software implemented for the evaluation of course correspondingly adapted - converter electronics can be used.

The invention and further advantageous embodiments thereof are explained in more detail below with reference to exemplary embodiments, which are illustrated in the figures of the drawing. Identical parts are provided in all figures with the same reference numerals; if it requires the clarity or it appears otherwise useful, is omitted reference numerals already mentioned in subsequent figures. Further advantageous embodiments or developments, esp. Combinations initially only individually explained aspects of the invention will become apparent from the figures of the drawing as well as the dependent claims per se.

Fig. 1a, b

eine Variante eines als Kompakt-Meßgerät ausgebildetes Meßsystem für in Rohrleitungen strömende Medien in verschiedenen Seitenansichten;

Fig. 2a, b

eine weitere Variante eines als Kompakt-Meßgerät ausgebildetes Meßsystem für in Rohrleitungen strömende Medien in verschiedenen Seitenansichten;

Fig. 3

schematisch nach Art eines Blockschaltbildes eine, insb. auch für ein Meßsystem gemäß den Fig. 1a, 1b, 2a, 2b, geeignete, Umformer-Elektronik mit daran angeschlossenem Meßwandler vom Vibrationstyp;

Fig. 4, 5

in, teilweise geschnittenen bzw. perspektivischen, Ansichten eine Variante eines, insb. für ein Meßsystem gemäß den Fig. 1a, 1b geeigneten, Meßwandlers vom Vibrations-Typ;

Fig. 6, 7

in, teilweise geschnittenen bzw. perspektivischen, Ansichten eine weitere Variante eines, insb. für ein Meßsystem gemäß den Fig. 2a, 2b geeigneten, Meßwandlers vom Vibrations-Typ;

Fig. 8 bis 11

Ergebnisse von im Zusammenhang mit der Erfindung, insb. auch unter Anwendung von computerbasierten Simulationsprogrammen und/oder mittels realer Meßsysteme im Labor, durchgeführten experimentellen Untersuchungen bzw. daraus abgeleitete, der Ermittlung einer Druckdifferenz in einem durch einen Meßwandler vom Vibrationstyp - etwa gemäß den Fig. 4, 5 bzw. 6, 7 - hindurchströmenden Medium dienende Kennlinienverläufe; und

Fig. 12

experimentell, insb. auch unter Anwendung von computerbasierten Simulationsprogrammen, ermittelte Druckverlustprofile in einem konventionellen Meßwandler vom Vibrationstyp.

In detail show:

Fig. 1a, b

a variant of a measuring device designed as a compact measuring device for flowing in pipes media in different side views;

Fig. 2a, b

a further variant of a measuring device designed as a compact measuring device for flowing in piping media in different side views;

Fig. 3

schematically in the manner of a block diagram, esp. Also for a measuring system according to the Fig. 1a, 1b . 2a, 2b suitable transducer electronics with vibration-type transducer connected thereto;

Fig. 4, 5

in, partially cut or perspective views, a variant of, esp. For a measuring system according to the Fig. 1a, 1b suitable vibrating type transducer;

Fig. 6, 7

in, partially cut or perspective views, a further variant of, esp. For a measuring system according to the Fig. 2a, 2b suitable vibrating type transducer;

8 to 11

Results of in the context of the invention, in particular also using computer-based simulation programs and / or by real measuring systems in the laboratory, carried out experimental studies or derived therefrom, the determination of a pressure difference in one by a transducer of the vibration type - such Fig. 4 . 5 or 6, 7 - flowing medium serving characteristic curves; and

Fig. 12

Experimental, esp. Using computer-based simulation programs, determined pressure loss profiles in a conventional vibration-type transducer.

In the Fig. 1a, 1b or 2a, 2b is a variant of a in a process line, such as a pipeline industrial plant, insertable, for example, by means of a Coriolis mass flowmeter, density meter, Viskositätsmeßgerät or the like formed, measuring system for flowable, esp. Fluid, media, shown, the in particular, the measuring and / or monitoring of a pressure difference of a medium flowing in the process line medium, possibly also measuring and / or monitoring at least one other physical quantity of the medium, such as a mass flow rate, a density, a viscosity or the like. The measuring system implemented here by means of an in-line measuring device of a compact design comprises a transducer of the vibration type connected to the process line via an inlet end # 111 and an outlet end # 112, which transducer is in operation corresponding to the medium to be measured, such as a low-viscosity liquid and / or a high-viscosity paste and / or a gas, flows through and to a, esp. In operation supplied externally via connecting cable and / or by means of internal energy storage with electrical energy, converter electronics ME of the measuring system is connected. This points, as in Fig. 3 shown schematically in the manner of a block diagram, serving to drive the transducer drive circuit Exc and a primary signals of the transducer MW processing, for example, by means of a microcomputer and / or in operation with the driver circuit Exc communicating, measuring and evaluation circuit μC is electrically connected to the measuring system, which supplies in operation the at least one measured variable, such as the instantaneous or a totalized mass flow, representing measured values. The driver circuit Exc and the evaluation circuit μC and other, the operation of the measuring system serving electronic components of the converter electronics, such as internal power supply circuits NRG for providing internal supply voltages U _N and / or the connection to a higher Meßdatenverarbeitungssystem and / or a communication bus COM serving a field bus, are also housed in a corresponding electronics housing 200, in particular impact-resistant and / or explosion-proof and / or hermetically sealed. For visualizing measuring system internally generated measured values and / or optionally measuring system internally generated status messages, such as an error message or an alarm on site, the measuring system further comprise at least temporarily communicating with the converter electronics display and control HMI, such as a in Electronics housing behind a window provided therein correspondingly placed LCD, OLED or TFT display and a corresponding input keyboard and / or a touch screen. In an advantageous manner, the converter electronics ME, in particular programmable and / or remotely configurable, can furthermore be designed so that they can be operated by the in-line measuring device with a superordinate electronic data processing system, for example a programmable logic controller (PLC), a personal computer and / or a workstation, via data transmission system, such as a fieldbus system and / or wirelessly, can exchange measurement and / or other operating data, such as current measurements or the control of the in-line meter setting and / or diagnostic values. In this case, the converter electronics ME, for example, have such an internal power supply circuit NRG, which is fed in operation by an external power supply provided in the data processing system via the aforementioned fieldbus system. According to one embodiment of the invention, the converter electronics is further designed so that they can be electrically connected to the external electronic data processing system by means of a, for example, configured as a 4-20 mA current loop, two-wire connection 2L and are supplied with electrical energy and measured values can transmit to the data processing system. In the event that the measuring system is intended for coupling to a fieldbus or other communication system, the converter electronics ME may have a corresponding communication interface COM for data communication in accordance with one of the relevant industry standards. The electrical connection of the transducer to the aforementioned converter electronics can by means of appropriate leads carried out, which are led out of the electronics housing 200, for example via cable bushing out and at least partially laid inside the transducer housing. The leads may be at least proportionally formed as electrical, at least partially wrapped in an electrical insulation wires, eg inform of "twisted pair" cables, ribbon cables and / or coaxial cables. Alternatively or in addition to this, the connection lines can also be formed, at least in sections, by means of conductor tracks of a, in particular flexible, optionally painted circuit board, cf. this also the aforementioned US-B 67 11 958 or US-A 53 49 872 ,

In the Fig. 4 and 5 and FIGS. 6 and 7, for further explanation of the invention, schematically illustrate a first and a second exemplary embodiment, respectively, for a vibration-type transducer MW suitable for the realization of the measuring system. The transducer MW is generally used to generate in a flowing medium, such as a gas and / or liquid, mechanical reaction forces, eg mass flow-dependent Coriolis forces, density-dependent inertial forces and / or viscosity-dependent frictional forces, the measurable, esp. Sensory detectable, on react back the transducer. Derived from these reaction forces, for example, a mass flow m, a density ρ and / or a viscosity η of the medium can be measured. Each of the transducers comprises for this purpose in each case a arranged in a transducer housing 100, the physical-electrical conversion of the at least one parameter to be measured actually acting inner part. In addition to receiving the inner part, the transducer housing 100 may also serve to support the electronics housing 200 of the in-line meter with driver and evaluation circuitry housed therein.

To guide flowing medium, the inner part of the transducer generally comprises at least a first - im in the Fig. 4 and 5 shown embodiment only at least partially curved - measuring tube 10, which extends between an inlet side first Meßrohrende 11 # and an outlet side second Meßrohrende 12 # with a swing length and vibrate to generate the aforementioned reaction forces during operation at least over its swing length and thereby to a static rest position oscillating, repeatedly deformed elastically. The oscillation length corresponds in this case to a length of an imaginary middle or also heavy line extending within lumens (imaginary connecting line through the center of gravity of all cross-sectional areas of the measuring tube), ie in the case of a curved measuring tube an elongated length of the measuring tube 10.

It should be expressly noted at this point that - although the transducer in the Fig. 4 and 5 has only a single curved measuring tube shown and at least insofar in its mechanical structure as well as its operating principle in the US-B 73 60 451 or the US-B 66 66 098 proposed by the applicant the type designation "PROMASS H", "PROMASS P" or "PROMASS S" commercially available transducers similar - for the realization of the invention, of course, can also serve transducers with straight and / or more than a measuring tube, approximately comparable to those in the above-mentioned US-A 60 06 609 . US-B 65 13 393 . US-B 70 17 424 . US-B 68 40 109 . US-B 69 20 798 . US Pat. No. 5,796,011 . US Pat. No. 5,731,527 or US-A 56 02 345 shown or, for example, on the part of the applicant under the type designation "PROMASS I", "PROMASS M" or "PROMASS E" or "PROMASS F" commercially available transducers each with two parallel measuring tubes. Accordingly, the transducer can also be a single straight measuring tube or at least two, for example by means of an inlet-side flow divider and an outlet-side flow divider, possibly additionally by means of at least one inlet-side coupling element and at least one outlet-side coupling element, mechanically coupled to each other and / or each other and / or identical curved and / or mutually parallel, measuring tubes for guiding medium to be measured, which vibrate during operation for generating the primary signals at least temporarily, such as frequency equal to a common oscillation frequency, but in opposite phase to each other. According to one embodiment of the invention, the transducer, such as in Fig. 6 and 7 shown schematically, therefore, in addition to the first measuring tube 10, a second measuring tube 10 'that on the inlet side by forming a first coupling zone by means of a, for example plate-shaped, first coupler element and forming a second coupling zone on the outlet side by means of one, for example, plate-shaped and / or identical to the first coupler element, second coupler element is mechanically connected to the first measuring tube 10. Also in this case, therefore, the first coupling zone defines respectively an inlet-side first measuring tube end 11 #, 11 '# of each of the two measuring tubes 10, 10' and the second coupling zone each having an outlet-side second measuring tube end 12 #, 12 '# of each of the two measuring tubes 10, 10 '. Since, in the event that the inner part is formed by means of two measuring tubes, each of the two, in particular. In operation substantially in phase opposition to each other oscillating and / or parallel and / or identical in terms of shape and material, measuring tubes 10, 10 'to the leading of serves measuring medium, opens each of the two measuring tubes according to a further embodiment of this second variant of the transducer according to the invention on the inlet side into one of two spaced flow openings of the dividing inflowing medium serving in two partial flows first flow divider 15 and the outlet side in each one of two spaced apart Flow openings of the re-merging of the partial flows serving second flow divider 16, so that so both measuring tubes are flowed through during operation of the measuring system simultaneously and in parallel by medium. Im in the Fig. 6 and 7 In the embodiment shown, the flow dividers are an integral part of the transducer housing insofar as the first end of the housing defining the inlet end # 111 of the transducer and by means of the second flow divider an outlet end second housing end defining the outlet end # 112 of the transducer.

As from the synopsis of FIGS. 4 and 5 or 6 and 7 readily apparent, the at least one measuring tube 10 is in each case shaped so that the aforementioned center line, as quite customary in transducers of the type in question, lies in an imaginary tube plane of the transducer. According to one embodiment of the invention, the at least one measuring tube 10 during operation is vibrated so that it oscillates about a vibration axis, esp. In a bending mode, the parallel to an imaginary connecting the two Meßrohrenden 11 #, 12 # imaginary connecting axis parallel or coincident is. The at least one measuring tube 10 is further shaped and arranged in the transducer, that said connecting axis extends substantially parallel to an inlet and outlet end of the transducer imaginary connecting imaginary longitudinal axis L of the transducer, possibly also coincident.

The at least one, for example made of stainless steel, titanium, tantalum or zirconium or an alloy thereof, measuring tube 10 of the transducer and insofar also extending within lumens imaginary center line of the measuring tube 10 may, for example, substantially U-shaped or, as in the Fig. 4 and 5 6 and 7, respectively, may be formed substantially V-shaped. Since the transducer should be used for a variety of different applications, esp. In the field of industrial measurement and automation technology, it is further provided that the measuring tube depending on the use of the transducer has a diameter in the range between about 1 mm and about 100 mm lies.

In order to minimize disturbances acting on the inner part formed by means of a single measuring tube, as well as to reduce the total amount of vibrational energy delivered to the connected process line by the respective measuring transducer, the inner part of the measuring transducer comprises according to the Fig. 4 and 5 embodiment shown further a mechanically coupled to the - here single curved - measuring tube 10, for example, similar to the measuring tube U- or V-shaped trained counter-oscillator 20. This is, as well as in Fig. 2 shown laterally spaced from the measuring tube 10 in the transducer and to form a - first aforementioned Meßrohrende 11 # defining - first coupling zone inlet side and the formation of a - second end of the second measuring tube 12 # defining - second coupling zone outlet side respectively fixed to the measuring tube 10. The - in this case substantially parallel to the measuring tube 10 extending, possibly also arranged coaxially to this - counteroscillator 20 is made of a tube with respect to the thermal expansion behavior compatible metal, such as steel, titanium or zirconium, and can be, for example, tubular or in be essential box-shaped also executed. As in Fig. 2 represented or among others in the US-B 73 60 451 proposed, the counteroscillator 20 may be formed for example by means of left and right sides of the measuring tube 10 arranged plates or on the left and right side of the measuring tube 10 arranged dummy tubes. Alternatively, the counter-oscillator 20 - like about in the US-B 66 66 098 suggested - be formed by means of a single side of the measuring tube and extending parallel thereto dummy tube. As if from a synopsis of FIGS. 2 and 3 can be seen, the counteroscillator 20 is supported in the embodiment shown here by means of at least one inlet-side first coupler 31 at the first Meßrohrende 11 # and at least one outlet side, esp. To the coupler 31 substantially identical, second coupler 32 at the second Meßrohrende 12 #. As a coupler 31, 32, for example, simple node plates can be used, which are fastened in a corresponding manner on the inlet side and the outlet side in each case to measuring tube 10 and counteroscillator 20. Furthermore, as in the in the Fig. 2 and 3 shown embodiment - a spaced apart in the direction of the imaginary longitudinal axis L of the transducer node plates together with protruding ends of the counteroscillator 20 inlet side and outlet side formed, completely closed box or possibly also partially open frame as a coupler 31 or as a coupler 32. As in the Fig. 2 and 3 schematically illustrated, the measuring tube 10 is further on the inlet side in the region of the first coupling zone opening straight first connecting pipe section 11 and on the outlet side in the region of the second coupling zone opening, esp. To the first connecting pipe section 11 substantially identical, straight second connecting pipe section 12 corresponding to the Medium supply or discharge - not shown here - connected process line, with an inlet end of the inlet side connecting pipe piece 11 practically form the inlet end of the transducer and an outlet end of the outlet side connecting pipe section 12, the outlet end of the transducer. Advantageously, the measuring tube 10 and together with the two connecting pipe pieces 11, 12 may be made in one piece, so that for their production, for example, a single tubular semi-finished product of a conventional transducer for such materials, such as stainless steel, titanium, zirconium, tantalum or corresponding alloys of it, can serve. Instead of that measuring tube 10, inlet tube piece 11 and outlet tube piece 12 are each formed by segments of a single, one-piece tube, these, if necessary, but also by means of individual, subsequently assembled, eg welded together, semifinished products are produced. Im in the Fig. 2 and 3 embodiment shown is further provided that the two connecting pipe pieces 11, 12, so to each other and to a two coupling zones 11 #, 12 # imaginary connecting imaginary longitudinal axis L of the transducer are aligned, that here formed by counter-oscillator and measuring tube inner part, along with twists the two connecting pipe pieces 11, 12, can oscillate about the longitudinal axis L. For this, the two connecting pipe pieces 11, 12 are aligned with each other so that the substantially straight pipe segments are substantially parallel to the imaginary longitudinal axis L or to the imaginary axis of vibration of the measuring tube that the pipe segments are aligned both to the longitudinal axis L and each other substantially. Since the two connecting pipe pieces 11, 12 are executed in the embodiment shown here practically over its entire length substantially straight, they are accordingly to each other as well as to the imaginary longitudinal axis L in aligned substantially. Like from the Fig. 2 and 3 Furthermore, this is, in particular compared to the measuring tube 10 bending and torsion-resistant, transducer housing 100, esp. Rigidly, at a distal to the first coupling zone inlet end of the inlet side connecting pipe section 11 and at a relation to the first coupling zone distal outlet end of the outlet side connecting pipe 12th fixed. In that regard, therefore, the entire - here by means of measuring tube 10 and counteroscillator 20 formed - inner part not only completely enveloped by the transducer housing 100, but also supported due to its own mass and the spring action of both connecting pipe pieces 11, 12 in the transducer housing 100 also capable of vibration.

For the typical case that the transducer MW is detachable with the, for example, formed as metallic pipe, process line to be mounted on the inlet side of the transducer a first flange 13 for connection to a medium feeding the measuring transducer line segment of the process line and the outlet side a second flange 14th provided for a medium from the transducer laxative line segment of the process line. The connecting flanges 13, 14 can, as in the case of transducers of the type described, also be integrated into the transducer housing 100 at the ends. If necessary, however, the connecting pipe pieces 11, 12 can also be connected directly to the process line, eg by means of welding or brazing. Im in Fig. 2 and 3 In the embodiment shown, the first connecting flange 13 are integrally formed on the inlet side connecting pipe piece 11 at its inlet end and the second connecting flange 14 is formed on the outlet side connecting pipe piece 12 at its outlet end, while in the in Fig. 4 and 5 shown embodiment, the connecting flanges are connected according to the corresponding flow dividers accordingly.

For actively exciting mechanical oscillations of the at least one measuring tube (or the measuring tubes), esp. On one or more of its natural natural frequencies, each of the in the Fig. 4 to 7 Furthermore, an electro-mechanical, esp. Electrodynamic, ie formed by means of dip-coil coils, excitation arrangement 40. This serves - driven by one supplied by the driver circuit of the converter electronics and, if necessary, in conjunction with the measuring and evaluation circuit, conditioned accordingly Exciter signal, eg with a regulated current and / or a regulated voltage, in each case by means of the driver circuit fed electrical excitation _energy or power E _exc in a on the at least one measuring tube 10, eg pulse-shaped or harmonic, acting and this in the previously described way deflecting excitation force F _exc convert. The excitation force F _exc may, as is usual with such transducers, be bidirectional or unidirectional and in the manner known to those skilled in the art, for example by means of a current and / or voltage control circuit, in terms of their amplitude and, for example by means of a phase-locked loop, be adjusted in terms of their frequency. As energizing arrangement 40, for example, an energizing arrangement 40 formed in a conventional manner by means of an electrodynamic vibration exciter 41, which acts for example in the region of half the oscillation length, ie in the region of half the oscillation length, can be used. The vibration exciter 41 may in the case of an inner part formed by means of counter-oscillator and measuring tube, as in Fig. 4 indicated, for example by means of a cylindrical exciting coil attached to the counteroscillator 20, which is flowed through during operation by a corresponding exciter current and thus is flooded by a corresponding magnetic field, as well as an at least partially immersed in the excitation coil permanent magnet armature, from the outside, especially in the center Measuring tube 10 is fixed, be formed. Further exciting arrangements for oscillations of the at least one measuring tube which are also suitable for the measuring system according to the invention are, for example, those mentioned in the introduction US-A 57 05 754 . US-A 55 31 126 . US-B 62 23 605 . US-B 66 66 098 or US-B 73 60 451 shown.

According to a further embodiment of the invention, the at least one measuring tube 10 is actively excited at least temporarily in use by means of the excitation arrangement in a Nutzmode in which, esp. Mainly or exclusively, bending vibrations to the imaginary imaginary vibration axis executes, for example, predominantly with exactly one natural natural frequency (Resonant frequency) of the respective and thus formed respectively inner part of the transducer, such as that corresponding to a bending vibration fundamental mode in which the at least one measuring tube has exactly one antinode. In particular, in this case it is further provided that the at least one measuring tube 10, as in such transducers with curved measuring tube quite common, so excited by the exciter _assembly to bending vibrations at an excitation frequency f _exc , that it is in Nutzmode to the aforementioned imaginary axis of vibration - oscillating approximately in the manner of a cantilevered cantilever, at least partially according to one of its natural bending modes. The bending oscillations of the measuring tube have an inlet-side node in the region of the inlet-side Meßrohrende 11 # defining inlet-side coupling zone and in the region of the outlet side Meßrohrende 12 # defining outlet-side coupling zone, so that the measuring tube with its oscillation length between these two nodes extends substantially free swinging. If necessary, the vibrating measuring tube but also, such as in the US-B 70 77 014 or the one JP-A 9-015015 proposed, by means of correspondingly in the range of the vibration length on the measuring tube additionally attacking resilient and / or electromotive coupling elements are selectively influenced in its oscillatory movements. The driver circuit may be formed, for example, as a phase-locked loop (PLL), which is used in the manner known in the art to constantly _adjust an excitation frequency, f _exc , the exciter _signal to the instantaneous natural frequency of the desired payload. The construction and use Such phase-locked loops for actively exciting measuring tubes to oscillations at a mechanical natural frequency is described, for example, in US Pat US-A 48 01 897 described in detail. Of course, other suitable for setting the excitation _energy E _exc suitable, known in the art and driver circuits, for example, according to the above-mentioned prior art, such as the above-mentioned US-A 47 77 833 . US-A 48 01 897 . US-A 48 79 911 . US-A 50 09 109 . US-A 50 24 104 . US-A 50 50 439 . US-A 58 04 741 . US-A 58 69 770 . US-A 6073495 or US-A 63 111 36 , Furthermore, reference should be made to the use of such vibrator-type drive circuits for the converter electronics provided with "PROMASS 83" transmitters , as described by the Applicant, for example, in conjunction with "PROMASS E", "PROMASS F" series transducers. PROMASS H "," PROMASS I "," PROMASS P "or" PROMASS S " . The driver circuit is, for example, in each case designed such that the lateral bending oscillations in the payload mode are regulated to a constant, thus also independent of the density, p, substantially independent amplitude.

To vibrate the least one measuring tube 10, the exciter assembly 40, as already mentioned, by means of a likewise oscillating excitation _signal of adjustable excitation frequency, f _exc fed so that the excitation coil of - here only on the measuring tube 10 attacking vibration exciter - in operation of one in his Amplitude correspondingly regulated excitation current i _{exc is} traversed, whereby the magnetic field required to move the measuring tube is generated. The driver or exciter _signal or its excitation current i _exc may be harmonic, multi-frequency or even rectangular, for example. The exciting frequency, f _exc , required for maintaining the bending vibrations of the at least one measuring tube 10 excitation current can be selected and adjusted in the embodiment shown in the embodiment advantageously so that the laterally oscillating measuring tube 10 at least predominantly oscillates in a bending vibration fundamental mode with a single antinode. Accordingly, according to a further embodiment of the invention, the excitation or Nutzmodefrequenz, f _exc , adjusted so that it corresponds as closely as possible to a natural frequency of bending vibrations of the measuring tube 10, esp. Of the Bieschwwingungsgrundmodes. When using a made of stainless steel, esp. Hastelloy, measuring tube with a caliber of 29 mm, a wall thickness s of about 1.5 mm, a swing length of about 420 mm and a stretched length, measured between the two Meßrohrenden, of 305 mm For example, at a density of virtually zero, eg in a measuring tube filled only with air, the resonant frequency corresponding to the bending mode fundamental mode would be approximately 490 Hz.

Im in the Fig. 4 and 5 shown embodiment with inner tube formed by means of measuring tube and counter-oscillator, the measuring tube 10 performs the excited by means of the energizing active bending oscillations predominantly relative to the counteroscillator 20, esp. On a common Oscillation frequency to each other in anti-phase. In the case of a simultaneously, for example, differential, acting on both measuring tube and counteroscillator exciter arrangement while the counteroscillator 20 is forcibly excited to simultaneous cantilever oscillations, in such a way that it equals frequency, but at least partially out of phase, esp. Essentially out of phase, for in Nutzmode oscillating measuring tube 10 oscillates. In particular, measuring tube 10 and counteroscillator 20 are further coordinated or excited so that they perform at least temporarily and at least partially counterparts, ie equal frequency, but substantially out of phase, bending vibrations about the longitudinal axis L during operation. The bending vibrations can be designed so that they are of uniform modal order and thus at least at rest fluid substantially uniform; in the other case, the use of two measuring tubes are these, as usual with transducers of the type in question, actively excited by the, esp. Differentially between the two measuring tubes 10, 10 'acting energizer arrangement so that they at least temporarily opposite bending vibrations in the operation Perform longitudinal axis L. In other words, the two measuring tubes 10, 10 'or measuring tube 10 and counter-oscillator 20 then each move in the manner of mutually oscillating tuning fork tines. In this case, according to a further embodiment of the invention, the at least one electro-mechanical vibration exciter is designed to gegengleiche vibrations of the first measuring tube and the second measuring tube, esp. Biegeschwingungen each of the measuring tubes to an imaginary connecting the respective first Meßrohrende and the respective second Meßrohrende imaginary Vibration axis, to stimulate or maintain.

For the operationally provided case that the medium flows in the process line and thus the mass flow m is different from zero, also Corioliskräfte be induced by means of vibrating in the manner described above measuring tube 10 in the medium flowing. These in turn act on the measuring tube 10 and thus cause an additional, sensory detectable deformation of the same, namely essentially according to a further natural natural mode of higher modal order than the Nutzmode. An instantaneous expression of this so-called Coriolis mode, which is superimposed on the excited useful mode with equal frequency, is dependent on the instantaneous mass flow rate m, especially with regard to its amplitudes. As Coriolis mode, as is common with such curved tube transducers, e.g. serve the natural mode of the anti-symmetric twist mode, ie those in which the measuring tube 10, as already mentioned, also executes torsional vibrations about a perpendicular to the bending axis imaginary axis of torsional vibration, which intersects the center line of the measuring tube 10 in the region of half the oscillation length imaginary.

For detecting oscillations, in particular bending oscillations, of the at least one measuring tube 10, for example also those in Coriolis mode, the measuring transducer furthermore has a corresponding sensor arrangement 50 in each case. This includes, as well as in the Fig. 4 to 7 schematic illustrated, one - spaced from the at least one vibration exciter - arranged on at least one measuring tube 10, for example electrodynamic, first vibration sensor 51, which provides a vibration of the measuring tube 10 representing serving as the first primary signal s _{1 of} the transducer Schwingungsmeßsignal, for example one corresponding to the vibrations Voltage or a current corresponding to the oscillations.

According to a development of the invention, the sensor arrangement further comprises a spaced apart from the first vibration sensor 52 at least one measuring tube 10, esp. Electrodynamic, second vibration sensor 52, which also provides a vibration of the measuring tube 10 representing serving as the second primary signal s _{2 of} the transducer Schwingungsmeßsignal , A length of the region of the associated at least one measuring tube extending between the two, for example, identical, vibration sensors extending, in particular substantially free-vibrating corresponds to a measuring length of the respective transducer. Each of the - here two, typically broadband - primary signals s ₁ , s _{2 of} the transducer MW in each case has a corresponding with the Nutzmode signal component with one of the instantaneous oscillation frequency, f _exc , the active excited in Nutzmode oscillating at least one measuring tube 10 corresponding signal frequency and a from the current mass flow of the medium flowing in at least one measuring tube 10 dependent phase shift relative to, for example by means of PLL circuit in response to an existing between at least one of the Schwingungsmeßsignale s ₁ , s ₂ and the excitation current in the exciter _arrangement existing phase difference, excitation _signal i _exc on , Even in the case of using a rather broadband excitation _signal i _exc can be assumed that the corresponding with the Nutzmode signal component of each of the primary signals other, esp. With any external interference corresponding and / or classify as noise due to the usually very high vibration quality of the transducer , Signal components predominates and so far is also dominating at least within a frequency range corresponding to a bandwidth of the Nutzmodes frequency range.

In the embodiments shown here, the first vibration sensor 51 on the inlet side and the second vibration sensor 52 are arranged on the outlet side at least one measuring tube 10, esp. From at least one vibration exciter or equidistant from the center of the measuring tube 10 as the first vibration sensor. As with such measuring instruments used in Coriolis mass flow meter, vibration sensors quite common, the first vibration sensor 51 and the second vibration sensor 52 are further arranged according to an embodiment of the invention each on a side occupied by the vibration exciter 41 of the measuring tube in the transducer , Furthermore, the second vibration sensor 52 can also be arranged on the side of the measuring tube occupied by the first vibration sensor 51 in the transducer. The In addition, vibration sensors of the sensor arrangement can advantageously be designed such that they supply primary signals of the same type, for example, in each case a signal voltage or a signal current. According to a further embodiment of the invention, both the first vibration sensor and the second vibration sensor are further each placed in the transducer MW, that each of the vibration sensors at least predominantly detects vibrations of at least one measuring tube 10. For the case described above, that the inner part is formed by means of a measuring tube and a counter-oscillator coupled thereto, according to a further embodiment of the invention, both the first vibration sensor and the second vibration sensor are formed and placed in the transducer so that each of the vibration sensors predominantly Vibrations of the measuring tube relative to the counteroscillator, for example, differentially detect, so that both the first primary signal s ₁ and the second primary signal s ₂ , esp. Counterparallel, represent oscillatory movements of at least one measuring tube 10 relative to the counteroscillator 20. For the other case described that the inner part is formed by means of two, esp. In operation gegengleich swinging, measuring tubes, according to another embodiment of the invention, both the first vibration sensor and the second vibration sensor is formed and placed in the transducer so that each of the Vibration sensors predominantly oscillations of the first measuring tube 10 relative to the second measuring tube 10 ', for example, differentially detect, so that both the first primary signal s ₁ and the second primary signal s ₂ , esp. Counterparallel, represent oscillations of the two measuring tubes relative to each other, esp that - as usual in conventional transducers - the first primary signal generated by the first vibration sensor inlet side vibrations of the first measuring tube relative to the second measuring tube and the second primary generated by the second vibration signal output side vibrations of the first measuring tube relative represent the second measuring tube. According to a further embodiment of the invention, it is further provided that the sensor arrangement exactly two vibration sensors, that is, in addition to the first and second vibration sensor no further vibration sensors, and insofar corresponds to conventional sensor arrangements for transducers of the type in question with respect to the components used.

The oscillation measuring signals supplied by the sensor arrangement-here serving as first or second primary signals-each having a signal component with an instantaneous oscillation frequency, f _exc , of the at least one measuring tube 10 oscillating in the actively excited useful mode are, as in FIG Fig. 3 shown, the converter electronics ME and there then provided the measuring and evaluation circuit μC provided therein, where they are first preprocessed by means of a corresponding input circuit FE, esp. Pre-amplified, filtered and digitized, to then be suitably evaluated. As an input circuit FE as well as a measuring and evaluation circuit μC can in this case in conventional Coriolis mass flow meters for the purpose of converting the Primary signals used or determination of mass flow rates and / or totalized mass flows, etc. already used and established circuit technologies are used, for example, those according to the above-mentioned prior art. According to a further embodiment of the invention, the measuring and evaluating circuit μC is accordingly also realized by means of a microcomputer provided in the converter electronics ME, for example by means of a digital signal processor (DSP), and by means of program codes correspondingly implemented therein and running therein. The program codes can be persistently stored, for example, in a non-volatile data memory EEPROM of the microcomputer and, when it is started, loaded into a volatile data memory RAM integrated, for example, in the microcomputer. Processors suitable for such applications are, for example, those of the TMS320VC33 type marketed by Texas Instruments Inc. It goes without saying that the primary signals s ₁ , s _2, as already indicated, are to be converted into corresponding digital signals for processing in the microcomputer by means of corresponding analog-to-digital converters A / D of the converter electronics ME, cf. this, for example, the aforementioned US-B 63 11 136 or US-A 60 73 495 or also the aforementioned transmitters of the "PROMASS 83" series.

In the measuring system according to the invention, the converter electronics ME is used in particular by means of the first primary signal and / or by means of the driver signal and using a, for example, provided in the converter electronics volatile data memory RAM, first pressure measured value X _p1 , the one , For example, upstream of the inlet end of the transducer or downstream of the outlet end of the transducer, prevailing in the flowing medium, esp. Static, first pressure, p _Ref , represents to generate a different from this pressure reading X _p1 second pressure reading X _p2 , the represents a static second pressure, p _crit , prevailing in the flowing medium. The pressure represented by the first pressure measured value, p _ref , may be, for example, a static pressure impressed on the inlet side or outlet side of the transducer by means of a pump controlled and correspondingly controlled pump and / or adjusted by means of a correspondingly controlled valve, while For example, pressure represented by the second pressure reading X _p2 may be a static pressure prevailing within the medium flowing through the transducer, or a static pressure occurring downstream of the inlet end of the transducer for the measurement system as a whole. The first pressure measured value X _p1 can therefore be determined very simply by, for example, during operation from the mentioned superordinate data processing system to the converter electronics and / or from a pressure sensor connected directly to the converter electronics and connected to the measuring system transmitted and stored there in said volatile data memory RAM and / or in the nonvolatile data memory EEPROM. Therefore, the measuring system further comprises a pressure sensor communicating in operation with the transducer electronics, for example via a direct point-to-point connection and / or wirelessly, for detecting, for example, upstream of the inlet end of the transducer or downstream of the outlet end of the transducer. Alternatively, or in addition to the pressure reading X _p1 but also, for example, using, inter alia, from the above-mentioned in the medium-conducting pipeline prevailing static pressure US-B 68 68 740 . US-A 57 34 112 . US-A 55 76 500 . US-A 2008/0034893 or WO-A 95/29386 . WO-A 95/16897 known pressure measuring method, are determined by means of the converter electronics directly on the basis of at least one of the primary signals of the transducer.

According to the invention, the converter electronics are further provided for monitoring the measuring system or a piping system connected thereto for critical operating conditions based on the determined second pressure measured value X _p2 , for example the extent of a measurement inevitably provoked by the measuring transducer itself Pressure drop in the flowing medium and / or the associated risk of mostly harmful cavitation in the flowing medium due to excessive pressure drop. Therefore, according to the invention, the converter electronics is further configured to generate an alarm using the second pressure reading X _p2 , which causes too low a static pressure in the flowing medium and / or falls below a predefined, minimum allowable static pressure in the medium and / or the one, for example, only emerging, occurrence of cavitation in the medium suitably signaled, visually and / or acoustically perceptible, for example, in the environment of the measuring system. The alarm can be brought to the hearing for example by the mentioned display and control HMI on site for display and / or by a controlled by the measuring system horn.

For generating the second pressure measured value X ₂ , according to a further embodiment of the invention, it is provided that the converter electronics determine a pressure difference measured value X _Δp using at least one oscillation measuring signal supplied by the transducer and / or by means of the driver signal, which determines one of the flow represented in the transducer pressure drop or occurring between two predetermined reference points in the flowing medium pressure difference, for example, such that a first of the two reference points on the inlet side in the transducer and a second of the two reference points outlet located in the transducer and in this respect a total drop across the transducer pressure difference , Δp _total . Alternatively, however, the second reference point can also be set so that it is set up immediately in a range of expected minimum static pressure in the transducer, ie a range of increased risk of cavitation.

Based on the pressure difference measured value and the internally held first pressure measured value X _p1 , the second pressure measured value X _p2 can be generated by means of the converter electronics, for example by means of the function: X _p2 = X _p1 -X _Δp . In the event that the first pressure measured value X _p1 does not exactly represent that pressure in the medium which corresponds to one of the two reference points underlying the pressure difference measured value, for instance because the pressure sensor delivering the pressure measured value X _p1 or because the pressure -Measurements X _p1 supplying pump with control from the inlet end of the transducer is further removed, of course, the pressure value X _{p1 to} convert to the reference point, for example by appropriate deduction or supplement between the corresponding with the pressure value X _p1 measuring point and the known pressure drop occurring by the calibration of the measuring system. The pressure difference measured value can also be used to monitor the transducer or its pressure-reducing influence on the flow during operation. Therefore, the converter electronics is designed according to a further embodiment, using the pressure difference measured value, if necessary, to generate an alarm that exceeds a predefined maximum allowable lowering of a static pressure in the medium flowing through the transducer and / or one through the Transducers provoked too high a pressure drop, Δp _total , correspondingly signaled in the medium, for instance in a visually and / or acoustically perceptible manner on site.

The pressure difference measured value X _Δp itself can, for example, according to the in US-B 73 05 892 or the US-B 71 34 348 described by means of a transducer of the vibration type feasible method for measuring a pressure difference can be determined such that a useful as a pressure difference measured pressure drop based on a vibration response of at least one measuring tube on a multimodal vibration excitation and in the converter electronics deposited physical-mathematical models for a Dynamics of - designed here as a Coriolis mass flow meter - measuring system is determined in flowing through the transducer medium. Alternatively or in addition thereto and by means of the second primary signal and taking into account a Reynolds number determined for the flowing medium, a pressure difference occurring between two predetermined, for example, also located within the transducer, reference points in the flowing medium to measure, such as a side of the transducer itself in the flowing Medium provoked pressure drop. For this purpose, the converter electronics generates by means of the first and second primary signal as well as using an internal Reynolds number X _Re stored in the volatile data memory RAM, for example, which represents a Reynolds number, Re, for the medium flowing in the transducer. The Reynolds number measured value X _Re can be generated, for example, during operation by means of the driver signal and / or by means of at least one of the primary signals, for example according to one of those mentioned in the introduction US-B 65 13 393 described method directly in the converter electronics ME. Alternatively or in addition to this, the Reynolds number measured value X _Re , for example, can also be transmitted from the mentioned electronic data processing system to the converter electronics ME.

generiert, worin K_ζ,1, K_ζ,2, K_ζ,3, vorab experimentell, etwa im Zuge einer Kalibrierung des Meßsystems und/oder mittels computergestützter Berechnungen, z.B. mittels FEM bzw. CFD, ermittelte, insb. in der Umformer-Elektronik als Festwerte vorgehaltene, Meßsystemparameter sind, die letztlich auch den jeweiligen Ort der der zu ermittelnden Druckdifferenz zugrundeliegenden Referenzpunkte definieren. Die mittels dieser Meßsystemparameter gebildete Funktion, von der ein durch experimentelle Untersuchungen ermitteltes Beispiel in Fig. 9 gezeigt ist, stellt quasi eine zwischen der momentanen bzw. aktuell gültigen Reynoldszahl Re des strömenden Mediums und einem davon abhängigen, auf die momentane kinetische Energie, ρU², des im Meßwandler strömenden Mediums bezogenen spezifischen Druckabfall vermittelnde Druckabfall-Kennlinie des Meßsystems dar, deren daraus intern der Umformer-Elektronik generierte, im weiteren als Druckabfall-Koeffizienten X_ζ, bezeichneten Funktionswerte ${\mathrm{X}}_{\zeta }={\mathrm{K}}_{\varsigma ,1}+{\mathrm{K}}_{\varsigma ,2}\cdot {{\mathrm{X}}_{\mathrm{Re}}}^{{\mathrm{K}}_{\varsigma ,3}}$

lediglich von der momentanen Reynoldszahl abhängig sind. Die die Druckabfall-Kennlinie definierenden Meßsystemparameter K_ζ,1, K_ζ,2, K_ζ,3 können beispielsweise so gewählt sein, daß ein erster der Referenzpunkte im - hier durch das erste Gehäuseende des Meßwandler-Gehäuses gebildeten - Einlaßende #111 des Meßwandlers lokalisiert ist, und daß ein zweiter der Referenzpunkte im - hier durch das zweite Gehäuseende des Meßwandler-Gehäuses gebildeten - Auslaßende #112 des Meßwandlers lokalisiert ist, so daß also der Druckdifferenz-Meßwert X_Δp im Ergebnis eine vom Einlaßende bis hin zum Auslaßende im strömenden Medium insgesamt auftretende Druckdifferenz, Δp_total, repräsentiert, vgl. Fign. 9, 11 und 12. Die Meßsystemparameter und insoweit die Referenzpunkte können beispielsweise aber auch so gewählt sein, daß der Druckdifferenz-Meßwert X_Δp, wie in Fig. 10 dargestellt, einen maximalen Druckabfall, Δp_max , im innerhalb des Meßwandlers strömenden Medium unmittelbar repräsentiert. Dieser maximale Druckabfall, Δp_max , tritt bei Meßwandlern der in Rede stehenden Art, wie auch aus den in Fig. 12 exemplarisch für Meßwandler der in Rede stehenden Art dargestellten Druckverlustprofilen ersichtlich, zwischen dem durch das erste Gehäuseende gebildeten Einlaßende #111 des Meßwandlers und einem stromaufwärts des durch das zweiten Gehäuseende gebildeten Auslaßende #112 des Meßwandlers lokalisierten Bereich von erhöhter Turbulenz auf. Für diesen Fall, daß einer der beiden Referenzpunkte, durch entsprechende Wahl der Meßsystemparameter für den Druckabfall-Koeffizienten bzw. die Druckabfall-Kennlinie, an den vorab genau ermittelten Ort minimalen Drucks (Δp = Δp _max ) innerhalb des im Meßwandler strömenden Medium, gelegt ist kann also der zweite Druck-Meßwert X_p2 so ermittelt werden, daß er den minimalen statischen Druck innerhalb des im Meßwandler strömenden Mediums repräsentiert und somit im Betrieb des Meßsystems ohne weiteres festgestellt werden, ob innerhalb des Meßwandlers oder ggf. auch unmittelbar im stromabwärts desselben liegenden Auslaufbereich der angeschlossenen Rohrleitung mit einem unzulässig niedrigen statischen Druck im strömenden Medium zu rechnen ist.According to a further embodiment of the invention, the converter electronics determines the pressure difference measured value using the Reynolds number measured value X _Re as well as a measuring system internally, for example again in the volatile data memory RAM, held flow energy measured value X _Ekin , the one of a density, ρ , and a flow velocity, U, of the medium flowing in the measuring transducer dependent kinetic energy, ρU ² , represented by medium flowing in the transducer. For this purpose, a corresponding computational algorithm is further implemented in the converter electronics, which calculates the pressure difference measured value based on the, in Fig. 8 exemplified, relationship ${\mathrm{X}}_{\mathrm{Ap}}=\left({\mathrm{K}}_{\varsigma .1}+{\mathrm{K}}_{\varsigma .2}\cdot {{\mathrm{X}}_{\mathrm{re}}}^{{\mathrm{K}}_{\varsigma .3}}\right)\cdot {\mathrm{X}}_{\mathrm{Ekin}}$

in which K _{ζ, 1} , K _{ζ, 2} , K _{ζ, 3} , previously determined experimentally, for example in the course of a calibration of the measuring system and / or by means of computer-aided calculations, for example by means of FEM or CFD, in particular in the converter Electronics held as fixed values, measuring system parameters are, which ultimately also define the respective location of the basis of the pressure difference to be determined reference points. The function formed by these measuring system parameters, of which an example determined by experimental investigations Fig. 9 is shown, quasi represents a between the current or current Reynolds number Re of the flowing medium and a dependent on the instantaneous kinetic energy, ρU ² , of the medium flowing in the transducer flowing specific pressure drop mediating pressure drop characteristic of the measuring system, the resulting internally generated the converter electronics, hereinafter referred to as pressure drop coefficient X _ζ , designated function values ${\mathrm{X}}_{\zeta }={\mathrm{K}}_{\varsigma .1}+{\mathrm{K}}_{\varsigma .2}\cdot {{\mathrm{X}}_{\mathrm{re}}}^{{\mathrm{K}}_{\varsigma .3}}$

are only dependent on the current Reynolds number. For example, the measuring system parameters K _{ζ, 1} , K _{ζ, 2} , K _{ζ, 3} defining the pressure drop characteristic may be chosen such that a first of the reference points in the inlet end # 111 of the transducer formed here by the first housing end of the transducer housing is located, and that a second of the reference points in the - here formed by the second housing end of the transducer housing - outlet end # 112 of the transducer is located, so that therefore the pressure difference measured value X _Dp as a result, a from the inlet end up to the outlet end of the pouring Medium total occurring pressure difference, Δp _total , represents, cf. FIGS. 9 . 11 and 12 , The measuring system parameters and insofar as the reference points can, for example, however, also be selected such that the pressure difference measured value X _Δp , as in FIG Fig. 10 represented, a maximum pressure drop, Δ p _max , directly represented in flowing within the transducer medium. This maximum pressure drop, Δ p _max , occurs in transducers of Speech type, as well as from the in Fig. 12 As an example, for pressure transducers of the type in question, it can be seen between the inlet end # 111 of the transducer formed by the first housing end and an area of increased turbulence located upstream of the outlet end # 112 of the transducer formed by the second housing end. For this case, one of the two reference points, by appropriate choice of the measuring system parameters for the pressure drop coefficient or the pressure drop characteristic, to the pre-determined exactly minimum pressure location (Δ p = Δp _max ) within the flowing medium in the transducer set Thus, the second pressure value X _p2 can be determined so that it represents the minimum static pressure within the medium flowing in the transducer and thus be readily determined during operation of the measuring system, whether within the transducer or possibly immediately downstream thereof lying outlet region of the connected pipe with an impermissibly low static pressure in the flowing medium is to be expected.

Taking into account the pressure drop characteristic or the pressure drop coefficient X _ζ , the functional relationship proposed for determining the pressure difference measured value can be further simplified to the relationship X _Δp = X _ζ · X _Ekin .

des durch den Meßwandler geführten Mediums möglichst genau repräsentiert. Dafür erzeugt die Meß- und Auswerte-Schaltung gemäß einer weiteren Ausgestaltung der Erfindung im Betrieb wiederkehrend einen Phasendifferenz-Meßwert X_Δϕ, der die zwischen dem ersten Primärsignal s₁ und dem zweiten Primärsignal s₂ existierenden Phasendifferenz, Δϕ, momentan repräsentiert. Die Berechnung des Massendurchfluß-Meßwert X_m kann, unter Verwendung eines gleichfalls in der Umformer-Elektronik vorgehaltenen, eine Schwingungsfrequenz von Vibrationen, beispielsweise den oben erwähnten lateralen Biegeschwingungen des wenigstens einen Meßrohrs 10 im Nutzmode, repräsentierenden Frequenz-Meßwerts X_f somit beispielsweise basierend auf dem bekannten Zusammenhang: $${\mathrm{X}}_{\mathrm{m}}={\mathrm{K}}_{\mathrm{m}}\cdot \frac{{\mathrm{X}}_{\mathrm{\Delta }\varphi }}{{\mathrm{X}}_{\mathrm{f}}}$$

erfolgen, worin K_m ein vorab experimentell, z.B. im Zuge einer Kalibrierung des Meßsystems und/oder mittels computergestützter Berechnungen, ermittelter, z.B. im nichtflüchtigen Datenspeicher, als Festwerte intern vorgehaltener Meßsystemparameter ist, der zwischen dem hier mittels des Phasendifferenz-Meßwerts X_Δϕ und des Frequenz-Meßwerts X_f gebildten Quotienten und der zu messenden Massendurchflußrate, $\dot{m},$

entsprechend vermittelt. Der Frequenz-Meßwert X_f selbst kann auf einfache Weise z.B. anhand von den von der Sensoranordnung gelieferten Primärsignale oder auh anhand des wenigstens einen die Erregeranordnung speisenden Treibersignals in dem Fachmann bekannter Weise ermittelt werden.According to a further embodiment of the invention, the measuring and evaluating circuit μC is also used for determining the second pressure measured value X _p2 , in particular also for determining the required pressure difference measured value X _Δp and / or the required flow energy measured value X _Ekin , and / or the Reynolds number X _Re required for this purpose, using the primary signals s ₁ , s ₂ supplied by the sensor arrangement 50, for example by means of a primary signal s ₁ , s ₂ generated between the measuring tube 10, which oscillates proportionally in useful and Coriolis mode of the first and second vibration sensors 51, 52 detected phase difference, recurring a mass flow measurement value X _m to determine the mass flow rate to be measured, $\dot{m}.$

represented as accurately as possible of the guided through the transducer medium. For this purpose, the measurement and evaluation circuit according to a further embodiment of the invention in operation repeatedly produces a phase difference measured value X _Δφ , which currently represents the phase difference Δφ existing between the first primary signal s ₁ and the second primary signal s ₂ . The calculation of the mass flow rate measurement value X _m can thus, for example, based on a frequency of vibration, for example, the above-mentioned lateral bending vibrations of the at least one measuring tube 10 in the Nutzmode representing frequency measurement value X _f using a likewise held in the converter electronics the known context: $${\mathrm{X}}_{\mathrm{m}}={\mathrm{K}}_{\mathrm{m}}\cdot \frac{{\mathrm{X}}_{\mathrm{\Delta }\phi }}{{\mathrm{X}}_{\mathrm{f}}}$$

in which K _{m is} a measuring system parameter determined beforehand experimentally, eg in the course of a calibration of the measuring system and / or by means of computer-aided calculations, for example in the non-volatile data memory, as fixed values between the here by means of the phase difference measured value X _Δφ and the Frequency measured value X _f formed quotient and the mass flow rate to be measured, $\dot{m}.$

mediated accordingly. The frequency measured value X _f itself can be determined in a simple manner, for example on the basis of the primary signals supplied by the sensor arrangement or also on the basis of the at least one driver signal supplying the exciter arrangement in a manner known to the person skilled in the art.

während unter Verwendung des Massendurchfluß-Meßwerts X_m und des Viskositäts-Meßwert X_η, auf einfache Weise der zur Ermittlung des Druckdifferenz-Meßwerts X_Δp benötigte Reynoldszahl-Meßwert X_Re in der Umformer-Eletronik ermittelt werden kann, etwa basierend auf der Beziehung ${\mathrm{X}}_{\mathrm{Re}}={\mathrm{K}}_{\mathrm{Re}}\cdot \frac{{\mathrm{X}}_{\mathrm{m}}}{{\mathrm{X}}_{\mathrm{\eta }}}.$

Die entsprechenden Meßsystemparameter K_Ekin bzw. K_Re sind im wesentlichen vom effektiven Strömungsquerschnitt des Meßwandlers abhängig und können vorab ohne weiteres, z.B. wiederum im Zuge einer Kalibrierung des Meßsystems und/oder mittels computergestützter Berechnungen, experimentell ermittelt und in der Umformer-Elektronik als meßsystemspezifische Festwerte abgelegt werden.According to a further embodiment, it is further provided that the converter electronics, for example in the volatile data memory RAM, a density measured value X _ρ , which currently represents a density to be measured, p, of the medium, and / or a viscosity measured value X _η , which currently represents a viscosity of the medium holds. Thus, based on the mass flow rate measured value X _m and the density measured value X _ρ , the flow energy measured value X _Ekin required for determining the pressure difference measured value X _Δp can thus be determined internally by means of the converter electronics, for example by means of conversion of the relationship ${\mathrm{X}}_{\mathrm{Ekin}}={\mathrm{K}}_{\mathrm{Ekin}}\cdot \frac{{\left({\mathrm{X}}_{\mathrm{m}}\right)}^2}{{\mathrm{X}}_{\mathrm{\rho }}}.$

while using the mass flow rate measurement value X _m and the viscosity measurement value X _η , the Reynolds number measurement value X _Re required for determining the pressure difference measurement value X _Δp can be easily determined in the converter electronics, based on the relationship, for example ${\mathrm{X}}_{\mathrm{re}}={\mathrm{K}}_{\mathrm{re}}\cdot \frac{{\mathrm{X}}_{\mathrm{m}}}{{\mathrm{X}}_{\mathrm{\eta }}},$

The corresponding measuring system parameters K _Ekin or K _Re are essentially dependent on the effective flow cross section of the transducer and can be readily determined in advance, for example once again in the course of a calibration of the measuring system and / or computer-aided calculations, and in the converter electronics as measuring system-specific fixed values be filed.

$${\mathrm{X}}_{\mathrm{\Delta p}}=\left({\mathrm{K}}_{\varsigma ,1}+{\mathrm{K}}_{\varsigma ,2}\cdot {{\mathrm{X}}_{\mathrm{Re}}}^{{\mathrm{K}}_{\varsigma ,3}}\right)\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot \frac{{\left({\mathrm{X}}_{\mathrm{m}}\right)}^2}{{\mathrm{X}}_{\mathrm{\rho }}},$$

$${\mathrm{X}}_{\mathrm{\Delta p}}=\left[{\mathrm{K}}_{\mathrm{\varsigma },1}+{\mathrm{K}}_{\mathrm{\varsigma },2}\cdot {\left({\mathrm{K}}_{\mathrm{Re}}\cdot \frac{{\mathrm{X}}_{\mathrm{m}}}{{\mathrm{X}}_{\mathrm{\eta }}}\right)}^{{\mathrm{K}}_{\varsigma ,3}}\right]\cdot {\mathrm{X}}_{\mathrm{Ekin}},$$

oder $${\mathrm{X}}_{\mathrm{\Delta p}}=\left[{\mathrm{K}}_{\varsigma ,1}+{\mathrm{K}}_{\varsigma ,2}\cdot {\left({\mathrm{K}}_{\mathrm{Re}}\cdot \frac{{\mathrm{X}}_{\mathrm{m}}}{{\mathrm{X}}_{\mathrm{\eta }}}\right)}^{{\mathrm{K}}_{\varsigma ,3}}\right]\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot \frac{{\left({\mathrm{X}}_{\mathrm{m}}\right)}^2}{{\mathrm{X}}_{\mathrm{\rho }}}.$$

Taking into account the aforementioned functional relationships, the pressure difference measured value X _{Δp can} also be determined based on one of the following relationships: $${\mathrm{X}}_{\mathrm{Ap}}={\mathrm{X}}_{\mathrm{\zeta }}\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot \frac{{\left({\mathrm{X}}_{\mathrm{m}}\right)}^2}{{\mathrm{X}}_{\mathrm{\rho }}}.$$

$${\mathrm{X}}_{\mathrm{Ap}}=\left({\mathrm{K}}_{\varsigma .1}+{\mathrm{K}}_{\varsigma .2}\cdot {{\mathrm{X}}_{\mathrm{re}}}^{{\mathrm{K}}_{\varsigma .3}}\right)\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot \frac{{\left({\mathrm{X}}_{\mathrm{m}}\right)}^2}{{\mathrm{X}}_{\mathrm{\rho }}}.$$

$${\mathrm{X}}_{\mathrm{Ap}}=\left[{\mathrm{K}}_{\mathrm{\varsigma }.1}+{\mathrm{K}}_{\mathrm{\varsigma }.2}\cdot {\left({\mathrm{K}}_{\mathrm{re}}\cdot \frac{{\mathrm{X}}_{\mathrm{m}}}{{\mathrm{X}}_{\mathrm{\eta }}}\right)}^{{\mathrm{K}}_{\varsigma .3}}\right]\cdot {\mathrm{X}}_{\mathrm{Ekin}}.$$

or $${\mathrm{X}}_{\mathrm{Ap}}=\left[{\mathrm{K}}_{\varsigma .1}+{\mathrm{K}}_{\varsigma .2}\cdot {\left({\mathrm{K}}_{\mathrm{re}}\cdot \frac{{\mathrm{X}}_{\mathrm{m}}}{{\mathrm{X}}_{\mathrm{\eta }}}\right)}^{{\mathrm{K}}_{\varsigma .3}}\right]\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot \frac{{\left({\mathrm{X}}_{\mathrm{m}}\right)}^2}{{\mathrm{X}}_{\mathrm{\rho }}},$$

The aforementioned, for the determination of the pressure difference measured value required measuring system parameters K _{ζ, 1} , K _{ζ, 2} , K _{ζ, 3} or K _Ekin or K _Re respectively required defined flows with known Reynolds numbers , Re, known kinetic energy, ρU ² , and known pressure curve can be realized sufficiently accurate on corresponding calibration systems readily, for example by means of the flow characteristics of known calibration media, such as water, glycerol, etc., which are guided by means of appropriately controlled pumps to each measuring system to be calibrated as embossed flow. Alternatively or in addition to the required for the determination of Meßsystemparameter flow parameters, such as the Reynolds number, the kinetic energy, the pressure difference, etc., for example, by means of a pressure difference measuring system can be determined by measurement, which together with the measuring system to be calibrated in the mentioned in the beginning US-B 74 06 878 forms proposed measuring systems and which is acted upon for the purpose of a wet calibration with flows with correspondingly varied mass flow rates, densities and viscosities.

Using the pressure difference measured value X _Δp , it is also possible to increase the phase difference between the primary signals s ₁ , s ₂ , which is also influenced to some extent by the pressure conditions in the flowing medium, or the likewise influenced oscillation frequency in order to increase the measuring accuracy of mass flow and / or or correct the density measured value during operation.

worin K_ρ,1, K_ρ,2, vorab experimentell ermittelte, beispielsweise im nichtflüchtigen Datenspeicher RAM, als Festwerte intern vorgehaltene Meßsystemparameter sind, die zwischen der durch den Frequenz-Meßwert X_f repräsentierten Schwingungsfrequenz und der zu messenden Dichte, p, entsprechend vermitteln.The measuring and evaluation circuit of the measuring system according to the invention is also used according to a further embodiment of the invention, derived from the currently represented by the frequency measurement value X _f oscillation frequency in the expert and in a known manner in addition to the determination of the pressure difference Measured value X _ρ required, for example, based on the relationship: $${\mathrm{X}}_{\mathrm{\rho }}={\mathrm{K}}_{\mathrm{\rho }.1}+\frac{{\mathrm{K}}_{\mathrm{\rho }.2}}{{\mathrm{<figure-callout\; id="2"\; label="X\; f"\; filenames="imgf0007.png,imgf0008.png"\; state="\{\{state\}\}">X\; </figure-callout>}}_{\mathrm{f}}^{\mathrm{}}}.$$

wherein K _{ρ, 1} , K _{ρ, 2} , previously determined experimentally, for example in the non-volatile data memory RAM, as fixed values internally stored measuring system parameters that mediate between the represented by the frequency measurement X _f oscillation frequency and the density to be measured, p ,

Alternatively or in addition to this, the evaluation circuit, as is customary with in-line measuring devices of the type in question, may also be used to determine the viscosity measured value X _η required for determining the pressure difference measured value, cf. this also the aforementioned US-B 72 84 449 . US-B 70 17 424 . US-B 69 10 366 . US-B 68 40 109 . US-A 55 76 500 or US-B 66 51 513 , To determine the excitation energy or excitation power or attenuation required for determining the viscosity, the exciter signal supplied by the driver circuit of the converter electronics, in particular, is suitable, in particular an amplitude and frequency of its current component driving the payload mode or also an amplitude of the total, possibly also to a detected by at least one of the primary signals vibration amplitude normalized excitation current. Alternatively or in addition, however, can also be used for adjusting the drive signal or the exciter current serving internal control signal or, for example, in the case of excitation of the vibrations of the at least one measuring tube with an excitation current of fixed or constant controlled amplitude, at least one of Primary signals, esp. An amplitude thereof, serve as a measure of the required for the determination of the viscosity measured value excitation energy or excitation power or attenuation.

The abovementioned, in particular also the calculating functions serving the generation of the pressure difference measured value X _Δp or other of the aforementioned measured values can be implemented very simply, for example by means of the abovementioned microcomputer of the evaluation circuit μC or, for example, also a digital signal processor DSP provided therein his. The creation and implementation of appropriate algorithms with the above Formulas corresponding or, for example, the operation of the above-mentioned amplitude or frequency control circuit for the excitation arrangement emulate, and their translation in the converter electronics corresponding executable program codes is familiar to the skilled person and therefore requires - at least in knowledge of the present invention - no detailed explanation. Of course, the aforementioned formulas or other realized with the converter electronics functionalities of the measuring system can also be readily realized in whole or in part by means of corresponding discretely constructed and / or hybrid, ie mixed analog-digital, arithmetic circuits in the converter electronics ME.

Claims (15)

1. Measuring system for flowing media, particularly media flowing through pipes, wherein said measuring system comprising:

   - a pipe

   - a vibronic-type transducer (MW) through which a medium flows during operation, particularly a gas and/or a liquid, a paste or a powder or another material which can flow, said transducer being designed to generate primary signals corresponding to parameters of the flowing medium, particularly a mass flow rate, a density and/or a viscosity,

   - a transmitter electronics module (ME) that is electrically coupled with the transducer and is designed to control the transducer and evaluate primary signals provided by the transducer,

   - and a pressure sensor communicating with the transmitter electronics module, said sensor being designed to measure a static first pressure p_Ref that is present in the pipe conducting the medium in the area upstream from an inlet end of the transducer or downstream from an outlet end of the transducer,

   - wherein the transducer (MW) comprises

   -- at least one measuring tube (10, 10') designed to conduct the flowing medium,

   -- at least an electromechanical, particularly electrodynamic, vibration exciter (41), which is designed to generate and maintain vibrations of the at least one measuring tube, particularly flexural vibrations of the at least one measuring tube around an imaginary axis of vibration which connects in an imaginary manner a first end of the measuring tube on the inlet side and a second end of the measuring tube on the outlet side with a natural resonance frequency of the transducer, and

   -- a first vibration sensor (51), particularly electrodynamic, designed to measure vibrations, particularly on the inlet side, of the at least one measuring tube, and to generate a first primary signal (si) of the transducer, representing vibrations, particularly on the inlet side, of the at least one measuring tube;

   - characterized in that the transmitter electronics module (ME) is designed to

   -- deliver at least one excitation signal (i_exc) for the vibration exciter, said signal causing vibrations, particularly flexural vibrations, of the at least one measuring tube, and

   -- generate a second pressure measured value (X_p2) using the first primary signal and/or the excitation signal and also using a first pressure measured value (X_p1), particularly maintained in a volatile data memory provided in the transmitter electronics module, said first pressure measured value representing the static first pressure, p_Ref , present in the flowing medium, wherein said second pressure measured value represents a static second pressure, p_Krit , present in the flowing medium, and wherein said second pressure measured value (X_p2) represents a static pressure, p_Krit, that is present in the flowing medium between an inlet end of the transducer and an outlet end of the transducer,

   - wherein the transmitter electronics module is designed to generate the second pressure measured value (X_p2) using a viscosity measured value (X_η), which represents a viscosity, η, of the medium flowing through the transducer, particularly in such a way that the transmitter electronics module generates the viscosity measured value (X_η) using the excitation signal and/or using the first primary signal,

   - and wherein the transmitter electronics module is designed to generate an alarm using the second pressure measured value (X_p2), said alarm signaling, particularly in a visually or acoustically recognizable manner, that a predefined minimum permitted static pressure in the medium is undershot.
2. Measuring system as claimed in the previous claim, wherein the transmitter electronics module is designed to generate an alarm using the second pressure measured value (X_p2), wherein said alarm signal the occurrence, particularly the imminent occurrence, of cavitation in the medium, particularly in a visually or acoustically recognizable manner.
3. Measuring system as claimed in one of the previous claims, wherein the transmitter electronics module is designed to determine the second pressure measured value (X_p2) using a Reynolds number measured value (X_Re), particularly maintained in a volatile data memory provided in the transmitter electronics module and/or generated using the excitation signal and/or using at least a primary signal provided by the transducer, wherein said Reynolds number measured value represents a Reynolds number, Re, for medium flowing through the transducer, particularly in such a way that the transmitter electronics module generates the Reynolds number measured value using the excitation signal and/or using the first primary signal and/or in that the transmitter electronics module generates the Reynolds number measured value using a viscosity measured value (X_η) that represents a viscosity, η, of medium flowing through the transducer.
4. Measuring system as claimed in one of the previous claims,

   - wherein the transducer comprises a second vibration sensor, particularly electrodynamic, designed to detect vibrations, particularly on the outlet side, at least of the at least one measuring tube and to generate a second primary signal of the transducer representing vibrations, particularly on the outlet side, at least of the at least one measuring tube, and

   - wherein the transmitter electronics module is designed to generate a mass flow measured value (X_m) using the first primary signal and using the second primary signal, wherein said measured value represents a mass flow rate, m, of medium flowing through the transducer.
5. Measuring system as claimed in one of the previous claims, wherein the transmitter electronics module is designed to generate the second pressure measured value (X_p2) using a density measured value (X_ρ), particularly maintained in a volatile data memory provided in the transmitter electronics module and/or generated using the excitation signal and/or using the first primary signal, said density measured value representing a density, p, of the medium flowing through the transducer.
6. Measuring system as claimed in one of the previous claims, wherein the transmitter electronics module is designed to generate a flow energy measured value (X_Ekin) using the first primary signal and using the second primary signal in order to determine the second pressure measured value (X_p2), said flow energy measured value representing a kinetic energy, ρU², of the medium flowing through the transducer, said energy being dependent on a density, p, and a flow velocity, U, of the medium flowing through the transducer.
7. Measuring system as claimed in Claims 4, 5 and 6, wherein the transmitter electronics module is designed to generate the flow energy measured value (X_Ekin) based on the following correlation: $${\mathrm{X}}_{\mathrm{Ekin}}={\mathrm{K}}_{\mathrm{Ekin}}\cdot \left({\left({\mathrm{X}}_{\mathrm{m}}\right)}^2/{\mathrm{X}}_{\mathrm{\rho }}\right),$$

   

   where K_Ekin is a measuring system parameter determined experimentally in advance, particularly during a calibration of the measuring system and/or using computer-assisted calculations, said parameter being maintained as a fixed value in the transmitter electronics module, particularly in a non-volatile data memory provided in the transmitter electronics module.
8. Measuring system as claimed in one of the previous claims, wherein the transmitter electronics module is designed to generate a pressure drop coefficient (X_ζ) to determine the second pressure measured value (X_p2), said coefficient representing a pressure drop over the transducer, which depends on the current Reynolds number, Re, of the flowing medium, in relation to a current kinetic energy of the medium flowing through the transducer, particularly based on the following correlation: $${\mathrm{X}}_{\mathrm{\zeta }}={\mathrm{K}}_{\mathrm{\zeta }.1}+{\mathrm{K}}_{\mathrm{\zeta }.2}\cdot {\mathrm{X}}_{\mathrm{Re}}\mathrm{power}{\mathrm{K}}_{\mathrm{\zeta }.3},$$

   

   where K_ζ.1, K_ζ.2, K_ζ.3 are measuring system parameters that are determined experimentally in advance and maintained as fixed values in the transmitter electronics module, particularly in a non-volatile data memory provided in the transmitter electronics module.
9. Measuring system as claimed in one of the previous claims, wherein the transmitter electronics module is designed to generate a pressure differential measured value (X_Δp) using the excitation signal and/or using the first primary signal, wherein said pressure differential measured value represents a difference in pressure occurring in the flowing medium between two predefined reference points, particularly in such a way that a first of the two reference points is located in the transducer on the inlet side and/or a second of the two reference points is located in the transducer on the outlet side.
10. Measuring system as claimed in the previous claim,

    - wherein the transmitter electronics module is designed to generate an alarm using the pressure differential measured value, wherein said alarm signals, in a visually or acoustically recognizable manner, that a predefined maximum permitted drop in static pressure in the medium flowing through the transducer is exceeded; and/or

    - wherein the transmitter electronics module is designed to generate an alarm using the pressure differential measured value, wherein said alarm signals, in a visually or acoustically recognizable manner, an excessively high pressure drop in the medium, said pressure drop being provoked by the transducer; and/or

    - wherein the transmitter electronics module is designed to generate the second pressure measured value (X_p2) using the pressure differential measured value.
11. Measuring system as claimed in one of the Claims 9 to 10,

    - wherein the transducer further comprises a transducer housing (100) with a first housing end on the inlet side, particularly having a connection flange for a pipe segment that conducts medium to the transducer, and with a second housing end on the outlet side, particularly having a connection flange for a pipe segment that conducts medium away from the transducer, and

    - wherein the pressure differential measured value (X_Δp) represents a difference in pressure occurring in the flowing medium overall from the first housing end through to the second housing end, particularly in such a way that a first reference point for the pressure difference represented by the pressure differential measured value (X_Δp) is located in the inlet-side first housing end of the transducer housing (100), and/or a second reference point for the pressure difference represented by the pressure differential measured value (X_Δp) is located in the outlet-side second housing end of the transducer housing (100).
12. Measuring system as claimed in Claim 11,

    - wherein the inlet-side first housing end of the transducer housing (100) is formed by means of a first flow divider (15) on the inlet side having two flow openings spaced at a distance from one another and the outlet-side second housing end of the transducer housing (100) is formed by means of a second flow divider (16) on the outlet side having two flow openings spaced at a distance from one another, and

    - wherein the transducer has two parallel measuring tubes designed to conduct flowing medium, wherein of said tubes

    -- a first measuring tube (10) enters into a first flow opening of the first flow divider (15) with an inlet-side first measuring tube end and enters into a first flow opening of the second flow divider (16) with an outlet-side second measuring tube end, and

    -- a second measuring tube (10') enters into a second flow opening of the first flow divider (15) with an inlet-side first measuring tube end and enters into a second flow opening of the second flow divider (16) with an outlet-side second measuring tube end,

    - wherein the at least one electromechanical vibration exciter is used to generate and/maintain mirror-inverted vibrations of the first measuring tube and of the second measuring tube, particularly flexural vibrations of each of the measuring tubes around an imaginary axis of vibration connecting in an imaginary manner the first measuring tube end and the second measuring tube end with a natural resonance frequency of the transducer, and

    - wherein the first primary signal generated using the first vibration sensor represents vibrations, particularly inlet-side vibrations, of the first measuring tube in relation to the second measuring tube.
13. Measuring system as claimed in one of the Claims 8 to 11, in connection with Claims 4, 5 and 6, wherein the transmitter electronics module is designed to generate the pressure differential measured value using the pressure drop coefficient (X_ζ), particularly based on the correlation: $${\mathrm{X}}_{\mathrm{\Delta p}}={\mathrm{X}}_{\mathrm{\zeta }}\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot \left({\left({\mathrm{X}}_{\mathrm{m}}\right)}^2/{\mathrm{X}}_{\mathrm{\rho }}\right),$$

    

    where K_Ekin is a measuring system parameter determined in advance and maintained as a fixed value in the transmitter electronics module, particularly in a non-volatile data memory provided in the transmitter electronics module.
14. Measuring system as claimed in one of the Claims 8 to 11, in connection with Claims 3, 4, 5 and 6, wherein the transmitter electronics module is designed to generate the pressure differential measured value according to the following correlation: $${\mathrm{X}}_{\mathrm{\Delta p}}=\left({\mathrm{K}}_{\mathrm{\zeta }.1}+{\mathrm{K}}_{\mathrm{\zeta }.2}\cdot {\mathrm{X}}_{\mathrm{Re}}\mathrm{power}{\mathrm{K}}_{\mathrm{\zeta }.3}\right)\cdot {\mathrm{K}}_{\mathrm{Ekin}}\cdot {\left({\mathrm{X}}_{\mathrm{m}}\right)}^2/{\mathrm{X}}_{\mathrm{p}}$$

    

    where K_ζ.1, K_ζ.2, K_ζ.3, K_Ekin are measuring system parameters that are determined experimentally in advance, particularly during a calibration of the measuring system and/or using computer-assisted calculations, and maintained as fixed values in the transmitter electronics module, particularly in a non-volatile data memory provided in the transmitter electronics module.
15. Measuring system as claimed in one of the Claims 9 to 14, wherein the transmitter electronics module is designed to generate a frequency measured value (X_f) to determine the pressure differential measured value (X_Δp) using the first primary signal and/or using the at least one excitation signal, wherein said frequency measured value represents a vibration frequency, f_exc, of vibrations of the at least one measuring tube, particularly flexural vibrations of the at least one measuring tube around an imaginary axis of vibration connecting in an imaginary manner a first end of the measuring tube on the inlet side and a second end of the measuring tube on the outlet side with a natural resonance frequency of the transducer.

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